Voltage reference devices



Sept. 18, 1956 w. G. EVANS VOLTAGE REFERENCE DEVICES Filed Feb. 5, 1953 Fig.|.

Fig.2.

INVENTOR WITNESSES: 14 /2 United States Patent VOLTAGE REFERENCE DEVICES William G. Evans, Pittsburgh, Pa.,

house Electric Corporation, poration of Pennsylvania Application February 5, 1953, Serial No. 335,335

6 Claims. (Cl. 321-19) assignor to Westing- East Pittsburgh, Pa., a corknown. However, these known static voltage reference devices also have certain limitations. For instance, the apparatus disclosed in application Serial No. 266,205, filed January 12, 1952, now Patent No. 2,725,515, and assigned to the same assignee as this invention, does not have a large power output for a given power input. On the other hand, other known static voltage reference devices do not maintain a substantially constant output voltage when the frequency of the input voltage is varied over a wide range.

An object of this invention is to provide a voltage reference device which has a substantially constant output voltage over a wide range in variation in the magnitude and frequency of the input voltage to the device, and a reference device which has a very low power consumption over this wide range of variation in the magnitude and frequency of the input voltage, by combining a ferroresonant constant potential device, whose average output voltage varies linearly with changes in the frequency of the input voltage, with a particular integrating network which cooperates in such a manner with the linear output of the constant potential device that the above desired results are obtained.-

Other objects of this invention will become apparent from the following description when taken in conjunction with the accompanying drawing in which:

Figure 1 is a schematic diagram of circuits and apparatus illustrating an embodiment of the teachings of this invention;

Fig. 2 is a schematic diagram of circuits and apparatus illustrating another embodiment of the teachings of this invention.

Referring to Fig. 1 of the drawing, there is illustrated a voltage reference device 10 comprising a transformer 12 having a magnetic core member 14, preferably formed from substantially rectangular hysteresis loop core material. In order to magnetically saturate the core member 14 in accordance with the input voltage of the voltage reference device 10, a primary winding 16 is disposed in inductive relationship with the core member 14. As illustrated, the primary winding 16 is connected in series circuit relationship with a capacitor 18, the series circuit being electrically connected in circuit relationship with input terminals 20 and 22. The input terminals 20 and 22 are supplied with a suitable alternating current voltage of variable frequency and magnitude, the voltage being of sufficient magnitude to effect a substantially complete saturation of the magnetic core member 14.

When the voltage across the input terminals 20 and 22 is of suflicient magnitude to effect a substantially complete saturation of the core member 14 and when the core member 14 is manufactured from substantially rectangular hysteresis loop core material, a ferro-resonant circuit is established by the capacitor 18 and the primary winding 16 of the transformer 12. By providing this ferroresonant circuit, the output voltage of the voltage reference device 10, as it appears across output terminals 24 and 26, remains substantially constant even though the magnitude of the input voltage across the input terminals 20 and 22 is varied over a Wide range.

As illustrated, a secondary winding 28 is disposed in inductive relationship with the magnetic core member 14 of the transformer 12. Since a ferro-resonant circuit, including the capacitor 18 and the primary winding 16 is established in the primary circuit of the transformer 12, the voltage across the secondary winding 28 is of substantially square wave shape. In addition, the average output voltage across the secondary winding 28 varies linearly with changes in the frequency in the voltage across the input terminals 20 and 22 since the core member 14 is substantially completely saturated during the operation of the voltage reference device 10.

In order to integrate the output voltage of the transformer 12 to thus maintain the output voltage of the voltage reference device 10 substantially constant over a range of at least 3 to 1 variation in the frequency of the input voltage across the terminals 20 and 22, a linear iron core inductance member 30 is electrically connected between the secondary winding 28 of the transformer 12 and a full-wave dry type rectifier 32, which is disposed to rectify the output current from the secondary winding 28 of the transformer 12. In particular, the inductance member 30 is electrically connected between one end of the secondary winding 28 and one of the input terminals of.

the rectifier 32, the other end of the secondary winding 28' being electrically connected to the other input terminal of the rectifier 32. In order for the inductance member 30 to properly function as an integrating device and thus have its impedance vary directly as the frequency of the voltage across the secondary winding 28 of the transformer 12, the value of the reactive impedance for the inductance member 30 must be large as compared to the resistance value of the load (not shown) connected to the output terminals 24 and 26 of the voltage reference device 10. When this condition exists, and when the inductance member 30 is connected in circuit with its associated components, as illustrated in Fig. 1, changes in the frequency of the input voltage as applied to the input terminals 20 and 22 effect substantially no changt in the integrated voltage wave which flows in the secondary circuit of the transformer 12. Such being the case, the voltage which appears across the output terminals 24 and 26 remains substantially constant over a range of at least 3 to 1 variation in the magnitude of the frequency of the voltage that appears across the input terminals 20 and 22.

In order that the voltage reference device 10 presents a high alternating current impedance to the load (not shown) connected to the output terminals 24 and 26, a linear iron core inductance member 34 is provided. In this instance, the inductance member 34 is connected between one of the output terminals of the rectifier 32 and the output terminal 26 of the voltage reference device 10. As illustrated, the other output terminal of the rectifier 32 is electrically connected to the output terminal 24 of the voltage reference device 10. It is to be noted, however, that the inductance member 34 presents a low impedance, as seen from the input side of the rectifier 32. This condition satisfies the requirement that the load (not shown) has a low impedance compared to the inductance member 30 in order for the inductance member 30 to function properly as an integrating means. Not only does the inductance member 34 provide the desired impedance but it likewise functions to filter the output current from the rectifier 32.

If one desires to obtain an extremely constant output voltage across the output terminals 24 and 26, a capacitor 36 is connected across the input terminals of the rcctifier 32. However, this same function can be accomplished by connecting the capacitor 36 across the output terminals of the rectifier 32. It is to be noted that the capacitor 36 and the inductance member 36 do not form a resonant circuit.

It is also to be noted that although the apparatus illustrated in Fig. l maintains the voltage across the output terminals 24 and 26 substantially constant over a wide range in the magnitude and frequency of the input voltage applied to the input terminals 20 and 22, it also has a large power output across the load (not shown), connected to the output terminals 24 and 26, for a given power input as applied to the input terminals 2 and 22. This low power loss feature is obtained by providing the ferro-resonant circuit, including the capacitor 18 and primary winding 16 of the transformer 12, and the integrating means or inductance member 39, both of which have an extremely low power loss.

Referring to Fig. 2, there is illustrated another embodiment of the teachings of this invention in which the same reference characters have been given to like components of the apparatus of Figs. 1 and 2. The main distinction between the apparatus illustrated in Figs. 1 and 2' is that in the apparatus illustrated in Fig. 2 a capacitor 4tl' is connected in parallel circuit relationship with the primary winding 16 of the transformer 12, instead of providing the series connected capacitor 18, as illustrated in Fig. 1. However, the capacitor 4t) and the primary winding 16, illustrated in Fig. 2 likewise forma ferro-resonant circuit, which ferro-resonant circuit performs the same function as that performed by the ferroresonant circuit illustrated in Fig. 1. However, in order to insure that the alternating current source (not shown) connected to the input terminals 20 and 22 presents a high impedance connected in parallel circuit relationship with the capacitor 40' to thus enable a ferns-resonant circuit to be established, a linear inductance member 42 is connected between the input terminals 2t) and 22 and the ferr'o-resonant circuit comprising the capacitor 4 and the primary winding 16 of the transformer 12. in particular, the inductance member 42 is connected between the input terminal 2i and the junction point of the capacitor 4d and the primary winding 1% of the transformer 12. However, as an alternative the inductance member 42 could be connected between the input terminal 22 and the other junction point of the capacitor 4i? and the primary winding 16. It is to be understood that a resistor .(not shown) could be substituted for the inducta'nce' member 42, however, it would consume considerably more power. Since the remaining apparatus illustrated in Fig. 2 is the same as the apparatus illustrated in Fig. l, a further description of the voltage reference device illustrated in Fig. 2 is deemed unnecessary.

The apparatus embodying the teachings of this invention has several advantages. For instance, it comprises all static components which have an extremely long life, particularly when compared to electronic components. in addition to comprising all static components, the apparatus embodying the teachings of this invention maintains with a high degree of accuracy a substantially constant output voltage over a wide range of variation in the magnitude and frequency of its input voltage. The apparatus embodying the teachings of this invention also has very low power consumption on both the primary and secondary sides of the transformer 12. i

Since various changes may be made in the foregoing embodiments of the invention without departing from the spirit and scope of the present invention, it is to be understood that the subject matter set forth hereinbefore shall be interpreted as illustrative and not in a limiting sense.

I claim as my invention:

1. In a voltage reference device, the combination comprising, input terminals for receiving a voltage of variable frequency and magnitude, a transformer having a magnetic core member consisting of substantially rectangular hysteresis loop core material, a primary winding disposed in inductive relationship with the core member, a capacitor, circuit means for so connecting the primary winding and the capacitor in circuit relationship with the input terminals that the capacitor and the primary winding form a ferro-resonant circuit provided the magnitude of the voltage across the input terminals is suflicient to substantially completely saturate the core member, a secondary winding disposed in inductive relation ship with the core member so that as the frequency of the voltage across the input terminals increases, with the magnitude of the voltage across the input terminals being suflicient to substantially completely saturate the core member, the average voltage across the secondary winding increases linearly, and a linear inductance member connected between the secondary winding and the output of the voltage reference device, whereby the output voltage of the voltage reference device remains substan tially constant even though the magnitude and frequency of the voltage across the input terminals vary over a wide range.

2. In a voltage reference device, the combination comprising, input terminals for receiving a voltage of variable frequency and magnitude, a transformer having a magnetic core member consisting of substantially rectangular hysteresis loop core material, a primary winding disposed in inductive relationship with the core member, a capacitor, circuit means for connecting the capacitor and the primary Winding in series circuit relationship and for connecting the series circuit to the input terminals so that the capacitor and primary winding form a ferro-resonant circuit provided the magnitude of the voltageacross the input terminals is suflicient to substantially completely saturate the core member, a secondary winding disposed in inductive relationship with the core member so that as the frequency of the voltage across the input terminals increases, with the magnitude of the voltageacross the input terminals being sufficient to substantially completely saturate the core member, the average voltage across the secondary winding increases linearly, and a linear inductance member connected between thesecondary winding and the output of the voltage reference device, whereby the output voltage of the reference device remains substantially constant even though the magnitude and frequency of the voltage across the input terminals vary over awide range.

3. In a voltage reference device, the combination comprising, input terminals for receiving a voltage of variable frequency and magnitude, a transformer having a magnetic core member consisting of substantially rectangular hysteresis loop core material, a primary winding disposed in inductive relationship with the core member, a capacitor connected inparallel circuit relationship with the primary winding, circuit means for connecting the primary winding and the capacitor to the input terminals so that the'capacitor and primary winding form a ferroresonant' circuit provided the magnitude of the voltage across the input terminals is suflicient to substantially completely saturate the core member, a secondary winding disposed in inductive relationship with the core member' so that as the frequency of the voltage across the input terminals increases, with the magnitude of the Voltag? 3IQ$ the input terminals being sufficient to substantially completely saturate the core member, the average voltage across the secondary winding increases linearly, and a linear inductance member connected between the secondary Winding and the output of the voltage reference device, whereby the output voltage of the voltage reference device remains substantially constant even though the magnitude and frequency of the voltage across the input terminal vary over a wide range.

4. In a voltage reference device disposed to supply energy to a load, the combination comprising, input terminals for receiving a voltage of variable frequency and magnitude, a transformer having a magnetic core member consisting of substantially rectangular hysteresis loop core material, a primary winding disposed in inductive relationship with the core member, a capacitor, circuit means for so connecting the primary winding and the capacitor in circuit relationship with the input terminals that the capacitor and primary winding form a ferroresonant circuit provided the magnitude of the voltage across the input terminals is suflicient to substantially completely saturate the core member, a secondary winding disposed in inductive relationship with the core member so that as the frequency of the voltage across the input terminals increases, with the magnitude of the voltage across the input terminals being sufiicient to substantially completely saturate the core member, the average voltage across the secondary winding increases linearly, a rectifier having input and output terminals, a linear inductance member connected between the secondary winding and the input terminals of the rectifier, another capacitor connected in circuit relationship with input terminals of the rectifier, and another linear inductance member connected between the output terminals of the rectifier and the output of the voltage reference device, whereby the output of the voltage reference device presents a high impedance to the load and has a substantially constant output voltage over a wide range of variation in the magnitude and frequency of the voltage across said input terminals for receiving a voltage of variable frequency and magnitude.

5. In a voltage reference device disposed to supply energy to a load, the combination comprising, input terminals for receiving a voltage of variable frequency and magnitude, a transformer having a magnetic core member consisting of substantially rectangular hysteresis loop core material, a primary winding disposed in inductive relationship with the core member, a capacitor, circuit means for connecting the capacitor and the primary winding in series circuit relationship and for connecting the series circuit to the input terminals so that the capacitor and the primary winding form a ferroresonant circuit provided the magnitude of the voltage across the input terminals is sufiicient to substantially completely saturate the core member, a secondary winding disposed in inductive relationship with the core member so that as the frequency of the voltage across the input terminals increases, with the magnitude of the voltage across the input terminals being sutficient to substantially completely saturate the core member, the average voltage across the secondary winding increases linearly, a rectifier having input and output terminals, a linear inductance member connected between the secondary winding and the input terminals of the rectifier, another capacitor connected across the input terminals of the rectifier, and another linear inductance member connected between the output terminals of the rectifier and the output of the voltage reference device, whereby the output of the voltage reference device presents a high impedance to the load and has a substantially constant output voltage over a wide range of variation in the magnitude and frequency of the voltage across said input terminals for receiving a voltage of variable frequency and magnitude.

6. in a voltage reference device disposed to supply energy to a load, the combination comprising, input terminals for receiving a voltage of variable frequency and magnitude, a transformer having a magnetic core member consisting of substantially rectangular hysteresis loop core material, a primary winding disposed in inductive relationship with the core member, a capacitor connected in parallel circuit relationship with the primary winding, circuit means for connecting the primary winding and the capacitor to the input terminals so that the capacitor and the primary winding form a ferro-resonant circuit provided the magnitude of the voltage across the input terminals is sufficient to substantially completely saturate the core member, a secondary winding disposed in inductive relationship with the core member so that as the frequency of the voltage across the input terminals increases, with the magnitude of the voltage across the input terminals being sufiicient to substantially completely saturate the core member, the average voltage across the secondary winding increases linearly, a rectifier having .input and output terminals, a linear inductance member connected between the secondary winding and the input terminals of the rectifier, another capacitor connected in circuit relationship with the input terminals of the rectifier, and another linear inductance member connected between the output terminals of the rectifier and the output of the voltage reference device, whereby the output of the voltage reference device presents a high impedance to the load and has a substantially constant output voltage over a wide range of variation in the magnitude and frequency of the voltage across said input terminals for receiving a voltage of variable frequency and magnitude.

References Cited in the file of this patent UNITED STATES PATENTS 2,221,456 Pohm et al. Nov. 12, 1940 2,297,673 Stevens Sept. 29, 1942 FOREIGN PATENTS 271,572 Switzerland Feb. 1, 1951 325,199 Italy Mar. 4, 1935 

